You child’s problem is speech delay, so far I could understand from your mail. If a child of two years does not utter two word sentences then probably he/she is suffering from speech delay. Speech delay can occur alone or along with delay of other developmental domains. I need more information- Can he produce any sounds? Did he ever utter any consonant like coo, boo etc? Does he turn head to any sounds or noise? Was he a premature baby? What about his intelligence development? Is there any positive history in your family of speech delay? Is it speech delay or language delay? Is he an absolutely normal child other than speech delay or having delay in other developmental domains? Speech delay means sound which is not understandable by others (stammering, articulation problem, problem in voice or fluency etc) and if the child is not able to use appropriate words according to age is language delay( problem to understand what other say or sharing his thoughts to others). There are certain causes of speech/language delay: learning disabilities, hearing problem, problem in articulating organs (like tongue, vocal cord, palate), intellectual disabilities, autism, traumatic brain injury, auditory processing disorder (problem with decoding sound speech), apraxia of speech (problem in sequencing and executing speech movements), selective mutism, neuromuscular problem (cerebral palsy. muscular dystrophy), premature delivery, hypothyroidism, Down syndrome and so on. To find out the exact cause we need to go through complete examination of the child, certain investigations .Patience is extremely needed because delay in speaking could be either a normal stage in development process or initial symptoms of behavior/psychiatric/neurological problems. Hearing assessment should be done along with ENT examinations and complete neurological examinations. Later on we need to perform IQ test, screening tests for autism (which you have done already), functional MRI of brain , language screening tests, developmental screening tests. As you have consulted two neurologists, they must have examined and investigated your child and finally passed their opinion. But at this stage you are not satisfied and seeking another opinion. I can understand your emotion. Now I have three suggestions for- 1. If your child has only speech delay you can take a third opinion from another neurologist (name mentioned in your mail box). If all three opines same then wait, observe and do continue the prescription 2. Consult an ENT specialist. 3. Make scope for your child to mix up with other peers of same age. Probably your child is getting speech therapy and don’t ignore it. If he has no other associated physical or laboratory abnormality the problem will be cured over time.